Fluid compressor



Aug. 13, 1929. F. M. BENNETT 1,724,553

FLUID COMPRESSOR Filed Jan. 23, 1925 4 Sheets-Sheet l 3mm Lbgl [Ma /med!attozwugdl Filed Jan. 23. 1925 4 Sheets-Sheet 3 .1 Guam M34 Aug. 13,1929. BENNETT 1,724,553

FLUID COMPRESSOR Filed Jan. 23. 1925 4 Sheets-Sheet 4 Ill-1 30 past thepiston rings.

50 nected to aneccentric upon Patented Aug. 13, 1929.

UNITED STATES FBANK BENNETT, orcAn'ron, onto- FLUID oomrnnsson.

application filed January This invention relatesto compressors such asare used for compressing ammonia gas and the like, and the objects ofthe improvement are to provide a compressor of either single or doublestage type, in'which the usual connecting rod between the piston andcrankshaft is eliminated, and in which the working parts are surroundedby lubricating fluid which absorbs the heat of compression; thelubricating oil being cooled by air, water orother cooling means. I

'The above and other objects may be attained by locating the cylinderand piston and other working parts within a water or air. cooled casingfilled with lubricating oil surrounding the working parts. 3 Theconnecting rod may be eliminated by mounting either the piston orcylinder to oscillate or rock upon trunnions within the casing, theother member being directly conjnectedto the driving shaft as by aneccentric or the like, the fluid being taken into the cylinder anddischarged therefrom through the trunnions which are provided withpacking to prevent leakage ofthe gas; means being provided forequalizingthe pressure to prevent leakage of atmospheric air into the casing ortoprevent pressure in the casing from equalizing with the-dischargepressure An embodiment of the inventionis illustrated in theaccompanying drawings, which- Figure 1 is a vertical, through a doublestage compressor constructed in accordance with the invention, showingthe condenser connected therewith; Fig. 2, a section on the line2%2,Fig. 1'; Fig. 3, an enlarged, longitudinal sectional view ofthe'cylinder and piston; and l,

Fig. .4, a. longitudinal sectional 'view through a single stagecompressor, [constructed in accordance with the invention.v

Similar numerals refer to similar parts throughout the drawings. 7

'Referring first to Figs. 1 to 3 inclusive, a two stage compressor isillustrated, in'which the cylinder is mounted to oscillate upon its trunnions, the piston being. directly lconthe, driving shaft by means ofwhich the piston is reciprocated and the cylinder oscillated; the oilcasing being arrangedto be water cooled in this form of compressor. I 1I The compressor casing l may be cast insectional View 23,1925. seal m,4, 345.

'tegrally with the'condenser'casing 2, the

usual coils 3 of which may be surrounded by a sheet metal casingLor'jacket 4, water being admitted at the upper endof the condenser casingas, at 5, and allowed to pass around the coils, between the jacket 4 andthe re ceiver drum 6, an outlet 7 being provided'in the upper portion ofthe casing, between the acket 4 and the compressor casing 1,"whereby allofthe water after passing downward around the coils, passes upward incontact with the compressor casing before'reaching the outlet, thustending to cool the compressor casing for a purpose hereinafter stated.The drive shaft may be in the form shown at 8, or, if'desired, may bethe usual crank shaft. An eccentric 9 is fixed upon the shaft and'issurrounded by an eccentric strap 10 directly connected to the end of thepiston 11, which is mounted for reciprocation within the cylinder 12.

The cylinder is arranged to oscillate uponthe'fhollow trunnions'l3mounted in the bearingsvl l and the intake and discharge connections'are'made through the pipes 15 and 16 respectively which are extendedthrough the t'runnions. H y

Leakage of the'lubricating oil indicated at A, into the intake;connection, .as well as leakage of the compressed or high pressure gasinto the oil, is prevented by packing 1 17 7 surrounding the inner endsof the intake and discharge pipes, within the hollow trunnions, aunitormpressure being placed upon the packingas by the springs 19. Y For the,purpose of preventing cating oil fromfbeing drawn into thecylinder,'-and disch'argedout of thecompressor, it is desirable toequalize the pressure within the casing I with the pressure of the incomthe lubriing gas. This may be accomplished as shownin Fig. 2,byproviding a" pipe 20 forminga connectionbetween the upper portion ofthe compressor casing '1 and the inlet pipe 15.

izing the pressureto prevent atmospheric air from .being drawn into thecompressor, by providing a breather pipe 21 "connected to the chamber 22of the piston', which receives gas at the intermediate pressure betweenthe twostages of compression, said pipe'extending into the upper portionof the compressor casing for equalizing thepressure therein withtheiintermediate' pressure of the gas.

' 1 In F- s, ilan'd 3 is shown a means of equaL The inlet pipe 15communicates with the eceiving chamber 22' in the cylinder head '23. Thegas passes out of the lower end of this chamber,through the annularslots 24, which are normally closed by means of a split ring valve '25seated in an annular groove 26 formed in the cylinder head.

The passage of the gas is then downward into the upper end of thecylinder and then through pocket 27 in the upper end of the piston, saidpocket having the annular slots 28 in its lower end, normally closed bythe split ring valve 29, located in the annular groove 30 Formed in thepiston communieating with the lower chamber 31 in the piston.

From this point, the gas passes downward into the piston, within thetube 32 and through the opening 33 in the lower end of said tube intothe chamber 22, which may communicate with the breather pipe 21, abovedescribed, as through the passage 34.

The greater portion of the gas, however, will be permitted to passupward around the outside of the tube 32 to the upper end of the pistonchamber 35, which communicates with the slots 36 normally closed by thesplit ring valve 37, which is mounted in an annular groove 38 in thepiston. Four radial lugs 39 retain the valve and piston ring, theremainder of the material being cut away as shown at 39, providingcommunicationwith the compression chamber 40, formed betweentheshoulders 41 and 42 of the piston and cylinder respectively, byreducing the diameter of the lower portion of the piston as shown at 43.The usual piston rings 44 are provided around the up per enlargedportion 45 of the piston.

, The lower end of the compression chamber 40 is provided with theconical reduced portion 45 communicating with the slots 46 which arenormally closed by the discharge valve, preferably in the form of asplit ring 47, which controls the passageof the compressed gas from thecompression chamber 40 through the slots 46 and. 48 into the dischargechamber 49, which may be an annular chamber formed in the cylinder andcommunicating with the discharge passage 50, the upper end of whichcommunicates with the outlet or discharge pipe 16.

The usual piston rings 51 are located around the lower reduced portionof the piston, and it will thus be seen that since the pressure withinthe casing 1 is equalized with the incoming gas, by the connection 20'between the casing and the inlet pipe, the lubricating oil cannot be,drawn past the piston rings 51 into the cylinder and discharged out ofthe compressor, as there is at all times of the cycle of compressionoperation, a higher pressure in the lower portion of the cylinder thanin the casing 1.

In the operation of the compressor, the compression of gas is asfollows; the gas enters the chamber 22 through the inlet pipe 15 and asthe piston moves downward, or toward the shaft 8, the gas is drawnthrough the inlet valve 25.

As the piston returns, the gas just drawn in, passes through the splitring valve 29 the discharge port and thence out through the dischargepipe 16. v v

This construction forms of the extended piston a receiver which iscontinuously cooled by the lubricating oil surrounding the same, andthus cooling between the two stages of compression is effected,resulting in lower power consumption.

The lubricating oil within the casing 1 is, in turn, cooled by the waterfrom the condenser or by, the usual form of water jacketing surroundingthe casing, or water tubes passing through or around the same, or maybe. cooled by air as shown in Fig. 4.

.In this type of compressor, it i very important that the heat ofcompression which is absorbed by the oil, be transmitted to the othercooling element such aswate-r or air, to the greatest possible extent,as discharged gas temperatures of 300 F. to 350 F. are customary and itis necessary that the oil be kept below the flash point to preventdisastrous explosion of the oil vapor and the compressed gas.

Suitable oil level gau es may be provided to indicate whether sufiicientoil is carried in the casing, but these gauges form no part of thepresent invention and for thi reason are not shown on the drawings.

, In Fig. 4 the inventionis illustrated as applied to a single stagecompressor in which the piston 11 is mounted to oscillate upon hollowtrunnions 13 through which the gas is taken inand discharged, thecylinder 12' being directly connected to the eccentric 9', upon thedriving shaft 8', by the eccentric strap 10, and arranged to bereciprocated, the oil casing 1 being provided with air-cooling fins 55.v 1' The intake pipe 15' may be connected with the interior of thecasing by the pipe 20 in the manner illustrated at 20 in Fig.2. Thisequalize the pressure within the casing with the pressure of theincoming gas, and in order to prevent lubricating oil frombeing drawninto the cylinder and discharged out of the compressor, the compressedgasat discharge pressureis admitted to the radial passages 56 andintothe annular groove 57 formed in the piston between the upper and lowerssets of piston rings 58 and 59 respectively. i

Thus intake pressure is provided within the oil casing, while dischargepressure is placed between the twosets of rings upon the piston, therebypreventing the lubricating oil from'being drawn into the cylinder fromthe oil casing.

From the above, it will be evident that a compressor is provided whichmay be of either single or double stage type, in which the, cylinder andpiston are mounted for a combinedoscillatory, reciprocatory motionwithout the use of a connecting rod, the working parts being arranged tobe operated Within a casing containing lubrieatingv oil, the oilabsorbing'the heat of compression which is radiated through the wallsofthe casing as by air or water cooling or the like; means beingprovided forequalizing pressure within thecasing to prevent atmosphericair from being drawn into the casing and also to prevent lubricating oilfrom being drawn into the cylinder.

In Fig. 4 of the drawings the inlet pipe 15 communicates with thechamber in the trunnions 13. The gas passes out of the chamber 70through the pipe 71 to the chamber 72 in the head of the piston 11. Thegas then passes to the compression chamber 73 in the cylinder headthrough the annular slots 74, which are normally closed by means of thesplit ring valve 7 5 seated in an annular groove formed in the pistonhead.

Upon compression the gas passes from the compression chamber through theannular slots 76, which are normally closed by means of the split ringvalve 77 seated in an annular groove formed in the cylinder head, andthence through the hollow portion 78 of the piston which communicates asat 7 9 with the discharge connection 16 mounted in the left handtrunnion 13.

I claim I v 1. A compressor including a casing adapted to containlubricating oil, a driving shaft journaled in the casing, a cooperatingpiston and cylinder mounted in the casing, one of said cooperatingmembers being provided with trunnions journaled in the casing and theother cooperating member directly connected to the driving shaft, meansfor placing exhaust pressure between the rings of the piston forpreventing oil from being drawn into the cylinder and means forabsorbing the heat from the oil in the casing. 2. A compressor includinga casing adapted to contain lubricating oil, a driving shaft journaledin the casing, a cooperating piston and cylinder mounted in the casing,one of said cooperating members being provided 'withtrunnions journaledin the casto the driving shaft, means for placing exhaust pressurebetween the rings of the pistonforpreventing oil from being drawn intothe cylinder and means for absorbing the heat from the oil in thecasing.

3. A compressor including 'a casing adapted to contain lubricating oil,a driving shaft journaled in the casing .and provided with anieccentric,a cylinder. providedwith hollow trunnions journaled in the casing, gasinlet and discharge passages being connected to said hollow trunnions,a. piston within the cylinder provided with an cecentric band mountedupon said eccentric, and means for placing exhaust pressure between therings of the piston for preventing oil from being drawn intothe-cylinder.

4. A compressor including 'a casing adapted to contain lubricating oil,a driving shaft journaled in the casing and provided with an eccentric,-a cylinder provided with hollow trunnions journaled in the casing, gas

inlet and discharge passages being connected to said hollow trunnions, apiston within the cylinder provided with an eccentric band mounted uponsaid eccentric, and means for absorbing the heat from the oil in thecasing, and means for placing in-take gas pressure in the casing anddischarge gas pressure between the rings of the piston for preventingoil from being drawn into the cylinder.

5. A compressor including a casing adapted to contain lubricating oil, adriving shaft journaled in the casing and provided with an eccentric acylinder provided with hollow trunnions journaled in the casing, gasinlet and discharge passages being connected to said hollow trunnions, apiston within the cylinder provided with an eccentric band mounted uponsaid eccentric, means for absorbing the heat from the oil in the casing,and means for placing exhaust pressure between the rings of the pistonfor preventing oil from being drawn into the cylinder.

6. A two stage compressor including a cylinder, a piston mounted withinthe cylinder, gas inlet and discharge passages connected to opposite endportions of the cylinder, means whereby one stage of compression isproduced upon the up stroke of the piston and a second stage ofcompression upon the down stroke thereof, the piston being hollow andproviding a receiver, for the gas between stages of compression, andmeans communieating with the receiver for preventing atmospheric airfrom being drawn into the compressor.

7. A two stage compressor including a cylinder, a piston mounted withinthe cylinder, gas inlet and discharge passages connected to opposite endportions of the cylinder, means whereby one stage of compression isproduced upon the up stroke of the piston and a second stage ofcompression upon the down stroke thereof, the piston being hollow andproviding a receiver for the gas between stages of compression, andmeans within the piston for causing the gas to travel the full length ofthe piston to allow the maximum; cooling of gas in the piston.

8. A compressor including a cylinder, a hollow piston mounted in thecylinder and forming a receiver chamber, a first stage compressionchamber at one end portion of the cylinder, a second stage compressionchamber at the other end portion of the cylinder, means for conveyinggas through the piston from the first stage compression chamber to thereceiver'chamber of the piston and thence to the second stagecompression chamber, a non-return discharge valve in the piston forpreventing the gas from passing back from the receiver chamber to thefirst stage compression chamber and a non-return suction valve forpreventing the gas from passing back from the second stage compressionchamber to the receiver chamber.

of the piston for preventing oil from being drawn into the cylinder.

10. A compressor including a casmg adapted to contain lubricating oil, adriving shaft journaled in the casing, a cooperating piston and cylindermounted in the casing, one of said cooperating members being providedwith trunnions journaled in the casing and the other cooperating'memberdirectly connected to the driving shaft and means for placing intakepressure in the casing and discharge pressure between the rings of thepiston for preventing oil from being drawn into the cylinder.

In testimony that I claim the above, I have hereunto subscribed my name.

FRANK M. BENNETT.

